First-principles studies of solid halogens under pressure: scaling rules for properties among I2, Br2 and Cl2

We have theoretically studied the properties of solid iodine, bromine and chlorine under pressure, by employing the full-potential linear muffin-tin orbital method within the local density approximation (LDA). Furthermore, in this paper we study bromine by the use of the generalized gradient approximation (GGA) and compare the results with those obtained using LDA. We examine the pressure dependence of the frequencies of Raman-active Ag modes using the frozen-phonon method. We also examine the scaling rules and find that they hold for these band-theoretical results.